I'm really concerned about the way you put the receiver together, you cut the cross support to put the reciever tubes through it. This will weaken the cross tube which carries all of the load dramatically weakening it and with three cuts outs, I would be worried.
I have never seen a hitch done this way. Usually they are welded and gusseted with plates.
You could add some triangles on the sides from the receiver tubes to the cross tube to add some strength, or a top and bottom plate on each tube.